[UBSan][MIPS] Fix cast-overflow tests for mips big endian

This fixes the bug https://llvm.org/bugs/show_bug.cgi?id=24152
The float value resides in the first 4 bytes of ValueHandle for both mips and mipsel.

Reviewers: dsanders, samsonov
Subscibers: rsmith, hans, mohit.bhakkad, jaydeep, llvm-commits
Differential: http://reviews.llvm.org/D11448
llvm-svn: 243384

compiler-rt/lib/ubsan/ubsan_value.cc

@@ -83,7 +83,7 @@ FloatMax Value::getFloatValue() const {
 #endif
       case 32: {
         float Value;
-#if defined(__BIG_ENDIAN__)
+#if defined(__BIG_ENDIAN__) && !defined(__mips__)
        // For big endian the float value is in the second 4 bytes
        //  instead of the first 4 bytes.
        internal_memcpy(&Value, ((const char*)&Val)+4, 4);