Revert "Split the x86 host toolchain into glibc and musl variants"

This reverts commit 4fb4ef2242.

Reason for revert: crossed with aosp/1775072

Change-Id: Ied922850b810d82627ba4f9ee42f672cfe286c91

cc/testing.go

@@ -450,25 +450,6 @@ func commonDefaultModules() string {
 		cc_library_static {
 			name: "note_memtag_heap_sync",
 		}
-
-
-		cc_library {
-			name: "libjemalloc5",
-			host_supported: true,
-			no_libcrt: true,
-			nocrt: true,
-			default_shared_libs: [],
-			stl: "none",
-		}
-
-		cc_library {
-			name: "libc_musl",
-			host_supported: true,
-			no_libcrt: true,
-			nocrt: true,
-			default_shared_libs: [],
-			stl: "none",
-		}
 	`
 }