Updated heavy test timeouts (#59)

Author: casella

configs/heavy_tests.json

@@ -4,7 +4,7 @@
     "libraryVersion":"master",
     "libraryVersionNameForTests":"OB",
     "ulimitOmc":400,
-    "ulimitExe":600,
+    "ulimitExe":400,
     "ulimitMemory":62914560,
     "optlevel":"-O0 -march=native",
     "referenceFileExtension":"mat",
@@ -20,7 +20,7 @@
     "libraryVersion":"master",
     "libraryVersionNameForTests":"NB",
     "ulimitOmc":400,
-    "ulimitExe":600,
+    "ulimitExe":400,
     "ulimitMemory":62914560,
     "optlevel":"-Ofast -march=native",
     "referenceFileExtension":"mat",
@@ -37,7 +37,7 @@
     "libraryVersion":"master",
     "libraryVersionNameForTests":"NB",
     "ulimitOmc":300,
-    "ulimitExe":600,
+    "ulimitExe":800,
     "ulimitMemory":62914560,
     "optlevel":"-Ofast -march=native",
     "extraCustomCommands":["setCommandLineOptions(\"--newBackend\")"]