Initialize static TLS memory using module list

This implementation simply iterates over each static TLS module and
copies its initialization image into a new thread's static TLS block.

Bug: http://b/78026329
Test: bionic unit tests
Change-Id: Ib7edb665271a07010bc68e306feb5df422f2f9e6
diff --git a/libc/private/bionic_elf_tls.h b/libc/private/bionic_elf_tls.h
index e95560b..fee821e 100644
--- a/libc/private/bionic_elf_tls.h
+++ b/libc/private/bionic_elf_tls.h
@@ -115,3 +115,5 @@
   size_t module_count = 0;
   TlsModule* module_table = nullptr;
 };
+
+void __init_static_tls(void* static_tls);