Imatinib Recruiting Phase 1 Trials for Metastatic Malignant Solid Neoplasm / Metastatic Melanoma / Advanced Cancers / Unresectable Solid Neoplasm / Unresectable Melanoma / Pathologic Stage IV Cutaneous Melanoma AJCC v8 / Metastatic Gastrointestinal Stromal Tumor / Advanced Malignant Solid Neoplasm / Clinical Stage IV Cutaneous Melanoma AJCC v8 / C-KIT Tyrosine Kinase Protein Overexpression Treatment