[Cache][SPIRV] Fix flacky test... again

The underlying issue was that I forgot to clean the cache directory
before running the test. So the test ended up running sometimes on a
dirty cache yielding bad fails.

Since the code is only running a single comgr action that only converts
spirv->bc, the contents of the cache should be 2 files:
* the bitcode
* the cache timestamp

Author: jmmartinez

amd/comgr/test-lit/spirv-translator-cached.cl

@@ -12,12 +12,12 @@
 // RUN: export AMD_COMGR_CACHE=1
 // RUN: AMD_COMGR_CACHE_DIR=%t.cache spirv-translator %t.spv -o %t.translated.bc
 // RUN: COUNT=$(ls "%t.cache" | wc -l)
-// RUN: [ 3 -eq $COUNT ]
+// RUN: [ 2 -eq $COUNT ]
 
 // COM: Run again and check that the cache contents haven't changed
 // RUN: AMD_COMGR_CACHE_DIR=%t.cache spirv-translator %t.spv -o %t.translated.again.bc
 // RUN: COUNT=$(ls "%t.cache" | wc -l)
-// RUN: [ 3 -eq $COUNT ]
+// RUN: [ 2 -eq $COUNT ]
 
 // COM: Run again and check that the cache contents haven't changed
 // RUN: AMD_COMGR_CACHE_DIR=%t.cache spirv-translator %t.spv -o %t.translated.again.bc