Rollforward "Split asm and c flags and srcs in..."

This fixes a test and rolls forward I28cf7437ee96cdf2fdbcb1eda2303691cff08ba4

Test: m nothing
Test: See I28cf7437ee96cdf2fdbcb1eda2303691cff08ba4
Change-Id: I0e450c28e70087e406e7b562d7e772785f177379
diff --git a/bp2build/cc_library_conversion_test.go b/bp2build/cc_library_conversion_test.go
index 0a72937..454b153 100644
--- a/bp2build/cc_library_conversion_test.go
+++ b/bp2build/cc_library_conversion_test.go
@@ -311,7 +311,7 @@
         "//build/bazel/platforms/arch:arm64": ["-DHAVE_FAST_FMA=1"],
         "//conditions:default": [],
     }),
-    srcs = ["math/cosf.c"],
+    srcs_c = ["math/cosf.c"],
 )`},
 	})
 }
@@ -618,7 +618,7 @@
 
 func TestCcLibraryCppFlagsGoesIntoCopts(t *testing.T) {
 	runCcLibraryTestCase(t, bp2buildTestCase{
-		description:                        "cc_library cppflags goes into copts",
+		description:                        "cc_library cppflags usage",
 		moduleTypeUnderTest:                "cc_library",
 		moduleTypeUnderTestFactory:         cc.LibraryFactory,
 		moduleTypeUnderTestBp2BuildMutator: cc.CcLibraryBp2Build,
@@ -654,10 +654,12 @@
     name = "a",
     copts = [
         "-Wall",
-        "-fsigned-char",
-        "-pedantic",
         "-Ifoo/bar",
         "-I$(BINDIR)/foo/bar",
+    ],
+    cppflags = [
+        "-fsigned-char",
+        "-pedantic",
     ] + select({
         "//build/bazel/platforms/arch:arm64": ["-DARM64=1"],
         "//conditions:default": [],