This test launch script has been seen failing on some MacOS nodes:
https://github.com/openjdk/jdk8u/blob/master/hotspot/test/compiler/5091921/Test7005594.sh

The error is:
```
04:43:57.030 /Users/admin/workspace/workspace/Test_openjdk8_hs_extended.openjdk_x86-64_mac_testList_0/aqa-tests/openjdk/openjdk-jdk/hotspot/test/compiler/5091921/Test7005594.sh: line 51: 18.77 * 1024: syntax error: invalid arithmetic operator (error token is ".77 * 1024")
```

Analysis:
When MEM has a decimal point in it, the following bash code fails:
```
MEM="$(($MEM * 1024))"
```

One way to fix this is to change the above code to this:
```
MEM="$((${MEM/\.*/} * 1024))"
```

Since this script is only present in JDK8, this change will not be contributed to head and backported.