Add invalid riscv64 ELF files for the linker tests.

The libtest_empty.so was built by the "libtest_empty" build rule, and
the other files are copies of that with small edits made by the toybox
hexedit tool. I worked out what to edit in each case from a combination
of "what does the name imply?" and "what does a diff of the xxd output
of the corresponding two arm64 files show?".

I failed to produce a working (by which I mean "failing") local-tls
file despite my best efforts. I'm not sure what exactly it was about the
gold-generated files we didn't like, because the commentary implies that
this would be problematic:

    39: 0000000000000004     4 TLS     LOCAL  DEFAULT   12 tls_var_2

But it loads without complaint.

Test: ran locally
Change-Id: I3b9b2b4db1f8827243541cf13380c6ceb840f123
diff --git a/tests/Android.bp b/tests/Android.bp
index 71be058..9c6aec5 100644
--- a/tests/Android.bp
+++ b/tests/Android.bp
@@ -105,6 +105,9 @@
         arm64: {
             srcs: ["prebuilt-elf-files/arm64/libtest_invalid-rw_load_segment.so"],
         },
+        riscv64: {
+            srcs: ["prebuilt-elf-files/riscv64/libtest_invalid-rw_load_segment.so"],
+        },
         x86: {
             srcs: ["prebuilt-elf-files/x86/libtest_invalid-rw_load_segment.so"],
         },
@@ -128,6 +131,9 @@
         arm64: {
             srcs: ["prebuilt-elf-files/arm64/libtest_invalid-unaligned_shdr_offset.so"],
         },
+        riscv64: {
+            srcs: ["prebuilt-elf-files/riscv64/libtest_invalid-unaligned_shdr_offset.so"],
+        },
         x86: {
             srcs: ["prebuilt-elf-files/x86/libtest_invalid-unaligned_shdr_offset.so"],
         },
@@ -151,6 +157,9 @@
         arm64: {
             srcs: ["prebuilt-elf-files/arm64/libtest_invalid-zero_shentsize.so"],
         },
+        riscv64: {
+            srcs: ["prebuilt-elf-files/riscv64/libtest_invalid-zero_shentsize.so"],
+        },
         x86: {
             srcs: ["prebuilt-elf-files/x86/libtest_invalid-zero_shentsize.so"],
         },
@@ -174,6 +183,9 @@
         arm64: {
             srcs: ["prebuilt-elf-files/arm64/libtest_invalid-zero_shstrndx.so"],
         },
+        riscv64: {
+            srcs: ["prebuilt-elf-files/riscv64/libtest_invalid-zero_shstrndx.so"],
+        },
         x86: {
             srcs: ["prebuilt-elf-files/x86/libtest_invalid-zero_shstrndx.so"],
         },
@@ -197,6 +209,9 @@
         arm64: {
             srcs: ["prebuilt-elf-files/arm64/libtest_invalid-empty_shdr_table.so"],
         },
+        riscv64: {
+            srcs: ["prebuilt-elf-files/riscv64/libtest_invalid-empty_shdr_table.so"],
+        },
         x86: {
             srcs: ["prebuilt-elf-files/x86/libtest_invalid-empty_shdr_table.so"],
         },
@@ -220,6 +235,9 @@
         arm64: {
             srcs: ["prebuilt-elf-files/arm64/libtest_invalid-zero_shdr_table_offset.so"],
         },
+        riscv64: {
+            srcs: ["prebuilt-elf-files/riscv64/libtest_invalid-zero_shdr_table_offset.so"],
+        },
         x86: {
             srcs: ["prebuilt-elf-files/x86/libtest_invalid-zero_shdr_table_offset.so"],
         },
@@ -243,6 +261,9 @@
         arm64: {
             srcs: ["prebuilt-elf-files/arm64/libtest_invalid-zero_shdr_table_content.so"],
         },
+        riscv64: {
+            srcs: ["prebuilt-elf-files/riscv64/libtest_invalid-zero_shdr_table_content.so"],
+        },
         x86: {
             srcs: ["prebuilt-elf-files/x86/libtest_invalid-zero_shdr_table_content.so"],
         },
@@ -266,6 +287,9 @@
         arm64: {
             srcs: ["prebuilt-elf-files/arm64/libtest_invalid-textrels.so"],
         },
+        riscv64: {
+            srcs: ["prebuilt-elf-files/riscv64/libtest_invalid-textrels.so"],
+        },
         x86: {
             srcs: ["prebuilt-elf-files/x86/libtest_invalid-textrels.so"],
         },
@@ -289,6 +313,9 @@
         arm64: {
             srcs: ["prebuilt-elf-files/arm64/libtest_invalid-textrels2.so"],
         },
+        riscv64: {
+            srcs: ["prebuilt-elf-files/riscv64/libtest_invalid-textrels2.so"],
+        },
         x86: {
             srcs: ["prebuilt-elf-files/x86/libtest_invalid-textrels2.so"],
         },