CPU-dependent Test failures with PGI compilers

[drroe]

Some original discussion was in #840

Parts or all of the following tests fail when compiled with PGI compilers, but only for certain types of hardware:

Test_Cluster_RandomSieve/Test_Error.dat
Test_Cluster_Sieve/Test_Error.dat
Test_Cluster_SymmRMSD/Test_Error.dat
Test_CurveFit/Test_Error.dat
Test_EvalPlateau/Test_Error.dat
Test_GIST/Test_Error.dat

Failures occur on the following platforms:

• Intel(R) Xeon(R) Gold 6130 CPU @ 2.10GHz

Failures do not occur on the following platforms:

• Intel(R) Xeon(R) CPU E5-2670 0 @ 2.60GHz

It's possible the failures are optimization-related; e.g. the Intel 6130 supports AVX-512 while the E5-2670 does not. I will try compiling with no optimizations and see if the test failures go away.

[drroe]

Even with -O0 the tests still fail.

[drroe]

Using flags recommended by Blue Waters:

-m64 -mcmodel=medium -Mdalign -Mllalign -Munroll -Kieee -O2 -fastsse -Mipa=fast

results in the same test failures, plus Test_CCP4/Test_Error.dat.

[drroe]

Finally addressed by #876 !