Enforce -no-pie for compiling LTP tests on 18.04+ platforms

[chiache]

Some LTP tests (e.g., brk01) assumes the executables to be position-independent. As a result, these tests can fail on Ubuntu 18.04+ if -pie is adopted as the default for GCC 5+. To stablize these tests, we need to force -no-pie when compiling LTP binaries.

---

This change is 

[dimakuv]

Reviewed 1 of 1 files at r1.
Reviewable status: all files reviewed, all discussions resolved, not enough approvals from maintainers (1 more required)

[mkow]

assumes the executables to be position-independent.

I think you meant position-dependent?

Reviewed 1 of 1 files at r1.
Reviewable status: all files reviewed, 1 unresolved discussion, not enough approvals from maintainers (1 more required) (waiting on @chiache)

a discussion (no related file):
Can we set -no-pie only to tests which really require it? I think having randomization enabled should allow us to detect more bugs (though this makes the tests less deterministic).

---

[yamahata]

Reviewed 1 of 1 files at r1.
Reviewable status: all files reviewed, 1 unresolved discussion (waiting on @chiache)