[ Runtime ] var_export does not retain float-ness of 1.0 #9874

Describe the bug
var_export and var_export_pure do not maintain float-ness of floating point values that can be cleanly represented as an integer.

Standalone code, or other way to reproduce the problem
\var_export_pure(1.0);

Steps to reproduce the behavior:

1. Run var_export on a float (1.0)
2. Observe 1
3. Expect 1.0

Expected behavior

1.0

Actual behavior

1

Environment

• Operating system

Ubuntu 26.04

• Installation method

dockerhub hersheltheodorelayton/hhvm-full

• HHVM Version

HipHop VM 26.9.29 (rel) (packedptr)
Compiler: heads/hhvm-oss-20260929-0-g7770b7775daf4aa3c287d0ef0a0deadb77c2ed27
Repo schema: dc7e862078876bc8e004ef3ca127bf951d3f2e5c
hackc-4e6507a0c2cea669b32ee599dc2c481e376a53d7-26.9.29

Additional context
N/A