[powerpc] Remove XFAIL for sanitizer_coverage_no_prune.cc on powerpc64
This test case works fine on powerpc64 (both BE and LE).
//
// REQUIRES: has_sancovcc,stable-runtime
// UNSUPPORTED: i386-darwin
-// XFAIL: tsan,powerpc64,s390x,mips
+// XFAIL: tsan,s390x,mips
//
// RUN: %clangxx -O0 %s -S -o - -emit-llvm -fsanitize-coverage=trace-pc,bb,no-prune 2>&1 | grep "call void @__sanitizer_cov_trace_pc" | count 3
// RUN: %clangxx -O0 %s -S -o - -emit-llvm -fsanitize-coverage=trace-pc,bb 2>&1 | grep "call void @__sanitizer_cov_trace_pc" | count 2
